C120 outward opening system window vs C116

Quick Overview: C120 vs C116

Before diving into the detailed comparison, here's a high-level snapshot of what each window series brings to the table. Both models are built on 6060-T66 aluminum profiles with PA66GF25 thermal break strips and an outward-opening mechanism, but their engineering priorities diverge from there.

Frame Design & Aesthetics

The most visible difference between the C120 and C116 lies in their frame design philosophy. The C120 features a robust 119mm frame wall width with a full standard square cavity structure, engineered first and foremost for superior wind pressure resistance and deformation stability. This makes it an ideal choice for high-rise buildings and coastal areas where structural performance under extreme weather conditions is a primary concern. The nail-free rolled press mesh structure adds to the C120's durability, providing corrosion resistance and a stable, flush fit that maintains its appearance over years of use.

The C116, on the other hand, takes a decidedly more minimalist approach. With its 116mm frame and signature oblique press line featuring a slim 28mm visible frame, the C116 is designed for homeowners and designers who prioritize sleek, modern aesthetics. The slim medium mullion — just 22mm wide — maximizes the field of vision, creating an almost frameless look that lets natural light flood in and showcases outdoor views without heavy aluminum interruptions. The flush alignment between the glass sash and mesh screen, combined with a 14mm ultra-slim interior profile, delivers a clean, contemporary appearance that complements modern architectural styles perfectly.

Thermal Performance & Insulation

Thermal performance is where the engineering differences between these two series become most meaningful. The C120 achieves a thermal K-value of 1.6, thanks to its multi-cavity thermal break system with PA66GF25 insulation strips and a full square cavity structure that creates additional insulating air pockets. The frame, sash, and mesh are fully sealed with injection-molded structural adhesive, ensuring that there are no thermal bridges or air leakage paths through the assembly.

The C116 delivers a K-value of 1.7 with its 34mm–44mm multi-chamber insulation strips and unified isothermal line design. While slightly higher than the C120's rating, the C116 compensates with a thicker glass sash (81mm vs. 62mm), which can accommodate thicker insulated glass units for enhanced thermal and acoustic performance. The triple sealing strips with seamless welded corners provide excellent air and water tightness, and the unified isothermal line design ensures that the glass centerline, thermal break strip, and equal-pressure sealing strip all align on the same axis — minimizing thermal transfer through the window assembly.

For projects in climates with extreme temperature variations or strict energy efficiency requirements, the C120's lower K-value gives it a slight edge. However, the C116's thicker sash capacity means it can be paired with higher-performance glass to close the gap, making it a flexible choice for projects that want both slim aesthetics and strong thermal performance.

Glass Sash & Mullion Configuration

The glass sash and mullion design is one of the most significant differentiators between these two series. The C120 features a 62mm glass sash thickness with a 75/31mm mullion width. The wider mullion provides greater structural rigidity, which is particularly beneficial for larger window openings or installations in wind-prone areas. The full square cavity design of the C120's frame and mullion contributes to its superior wind load performance.

The C116 stands out with its 81mm glass sash — significantly thicker than the C120's — paired with a slim 58/22mm mullion. This combination is engineered for maximum glass area and minimum visible aluminum. The 22mm medium mullion is among the slimmest in the industry for outward-opening casement windows, and when combined with the oblique press line design, it creates a seamless, almost floating glass appearance. The thicker sash also allows for triple-glazing configurations or thicker laminated glass options, which can be important for acoustic insulation or safety requirements.

As a casement window supplier that serves both residential and commercial markets, ALPES has engineered these two series to address different market segments: the C120 for performance-driven applications and the C116 for design-forward projects where visual impact matters most.

Screen Mesh Options

Both window series come with integrated screen mesh as standard, but the options differ to match each series' design philosophy. The C120 comes standard with a 40# black stainless steel mesh, which provides a balance of visibility, durability, and insect protection. For those who want enhanced protection, optional upgrades include a Black High-Definition Anti-PM2.5 Mesh or 80# black/gray stainless steel mesh for finer filtration.

The C116 comes standard with 80# black or gray stainless steel mesh, offering finer mesh density right out of the box. It also offers the Black High-Definition Anti-PM2.5 Mesh as an option. The C116's flush alignment between the glass sash and mesh screen creates a more integrated appearance, where the screen doesn't visually protrude or disrupt the clean lines of the window design. This is a key aesthetic advantage for homeowners who want insect protection without compromising on the window's sleek profile.

Hardware & Security

Hardware is the unsung hero of any high-quality window system, and both the C120 and C116 are equipped with premium hardware from reputable European manufacturers. The C120 features a ROTO transmission box with anti-pry lock points, providing robust security for outward-opening applications. It also includes a fall rope safety mechanism and roller locking device under the ALPES brand, adding extra layers of safety for high-rise installations.

The C116 offers more flexibility in hardware selection, with 304 stainless steel high-load hinges with a built-in hardware groove as standard, and an optional upgrade to German Wehag hardware for those who want premium European craftsmanship. The C116 also provides two handle options: a baseless handle with a 90-degree design and a side-mount handle, allowing homeowners and designers to match the hardware style to their interior aesthetic. This level of customization is one of the reasons the C116 is favored in high-end residential projects where every design detail matters.

Drainage & Weather Resistance

Outward-opening windows face the brunt of wind-driven rain, so effective drainage systems are critical to long-term performance. The C120 relies on its comprehensive sealing system — with injection-molded structural adhesive sealing the frame, sash, and mesh — to keep water out. The high-strength corner reinforcement with complete corner sealing ensures that the most vulnerable points of the window remain watertight even under heavy wind and rain.

The C116 incorporates an easy drainage system with a flat-channel, obstacle-free design that allows water to escape quickly and efficiently. Combined with its triple sealing strips featuring seamless welded corners, the C116 provides excellent weather resistance while maintaining its slim profile. The unified isothermal line design also helps prevent condensation on interior surfaces by keeping the interior frame temperature closer to room temperature.

Which One Is Right for Your Project?

Shared Quality & Craftsmanship

Despite their differences, both the C120 and C116 share the same foundation of quality that defines ALPES as a premier casement window manufacturer. Both are constructed from 6060-T66 grade aluminum profiles with 1.8–2.0mm wall thicknesses that meet or exceed new national standards. Both feature PA66GF25 thermal break strips for excellent insulation performance. And both come with the same color options — Ice Cream White, Aurora Gray, Starry Sky Gray, and Brown Coffee — with custom color matching available for projects that require specific finishes.

Both series also benefit from ALPES's 100,000 m² manufacturing facility and advanced production technology, ensuring consistent quality across every unit produced. Whether you choose the performance-oriented C120 or the design-forward C116, you're getting a window system that's engineered to international building codes and backed by a manufacturer with global project experience, from luxury villas in Saudi Arabia and Dubai to modern residences in Australia.

Final Thoughts

The choice between the C120 and C116 ultimately comes down to what matters most for your specific project. If you're working on a high-rise building, a coastal property, or any application where structural performance and maximum thermal efficiency are the top priorities, the C120 Outward Opening System Window is the clear choice. Its robust square cavity design, lower K-value, and ROTO hardware with anti-pry security make it the workhorse of ALPES's casement window lineup.

If, on the other hand, you're designing a luxury home, a modern villa, or any project where aesthetic impact and panoramic views are central to the design vision, the C116 Outward-Open Window delivers a level of visual elegance that's hard to match. Its ultra-slim mullion, oblique press line design, and flush glass-and-mesh alignment create a window that feels more like a framed view than a building component — while still delivering solid thermal performance and security.

For large-scale projects or developments, it's not uncommon to use both series — C120 windows on upper floors or wind-exposed elevations, and C116 windows on primary living areas where the view is the star. Whichever you choose, both the C120 and C116 represent the kind of thoughtful engineering and quality manufacturing that has made ALPES a trusted name in premium aluminum window systems worldwide.